package utils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;

import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class DesEncrypter {
	Cipher ecipher;
    Cipher dcipher;

   public DesEncrypter(SecretKey key) {
        try {
            ecipher = Cipher.getInstance("DES");
            dcipher = Cipher.getInstance("DES");
            ecipher.init(Cipher.ENCRYPT_MODE, key);
            dcipher.init(Cipher.DECRYPT_MODE, key);

        } catch (javax.crypto.NoSuchPaddingException e) {
        } catch (java.security.NoSuchAlgorithmException e) {
        } catch (java.security.InvalidKeyException e) {
        }
    }

    public String encrypt(String str) {
        try {
            // Encode the string into bytes using utf-8
            byte[] utf8 = str.getBytes("UTF8");

            // Encrypt
            byte[] enc = ecipher.doFinal(utf8);

            // Encode bytes to base64 to get a string
            return new sun.misc.BASE64Encoder().encode(enc);
        } catch (javax.crypto.BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
        return null;
    }

    public String decrypt(String str) {
        try {
            // Decode base64 to get bytes
            byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

            // Decrypt
            byte[] utf8 = dcipher.doFinal(dec);

            // Decode using utf-8
            return new String(utf8, "UTF8");
        } catch (javax.crypto.BadPaddingException e) {
        	throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
        	throw new RuntimeException(e);
        } catch (UnsupportedEncodingException e) {
        	throw new RuntimeException(e);
        } catch (java.io.IOException e) {
        	throw new RuntimeException(e);
        }
    }
    
    public static void main(String[] args) {
    	try {
            // Generate a temporary key. In practice, you would save this key.
            // See also e464 Encrypting with DES Using a Pass Phrase.
            SecretKey key = KeyGenerator.getInstance("DES").generateKey();
            System.out.println("Key: " + key);
        
            // Create encrypter/decrypter class
            DesEncrypter encrypter = new DesEncrypter(key);
            
            String publicMessage = "Don't tell anybody!";
            System.out.println("Public message: " + publicMessage);
            // Encrypt
            String encrypted = encrypter.encrypt(publicMessage);
            System.out.println("Encrypted message: " + encrypted);
            // Decrypt
            String decrypted = encrypter.decrypt(encrypted);
            System.out.println("Decrypted message: " + decrypted);
        } catch (Exception e) {
        }
    }

}
